Telephone system.



1 ,nventor.

3 Attorneyys Patented Oct. l0, I899.

E. W. HAM.

TELEPHONE SYSTEM.

(Application filed June 13, 1898.)

2 SheetsSheet (No Model.)

m: nomus urns co Witnesses.

Patented Oct. [0, I899.

E. W. HAM.

TELEPHONE SYSTEM.

(Application filed. June 13, 1898.)

2 Sheets-Sheet 2,

(No Model.)

n O t n e v n I Witnesses. -&M a umawm W Wu Att rneyvs.

a wing rricsi EDIVIN \V. HAM, OF IVOROESTER, MASSACHUSETTS, ASSIGNOR TOILUMMER,

' HAM & RICHARDSON, OF SAMF PLACE.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 634,575, dated October10, 1899.,

Application filed June 13,1898. Serial No. 683,250. (No model.)

To all whom it may concern:

Be it known that I, EDWIN IV. HAM, a citi- Zen of the United States,residing at VVorcester, in the county of Worcester and State ofMassachusetts, have invented a new and useful Telephone System, of whichthe following is a specification.

My invention relates to a system of intercommunicating or connectedtelephones; and the object of my invention is to provide a simple,efficient, and inexpensive form of switchboard which is light, compact,and durable, so that the same canbe readily mounted in the casing of anordinary telephone instrument, and which will be positive in its actionand not liable to get out of order.

To this end my invention consists of the parts and combinations ofparts, as hereinafter described, and more particularly pointed out inthe claims at the end of this specifica tion.

In the accompanying two sheets of drawings, Figure 1 is a transversesectional view of a telephone-switchboard constructed according to myinvention. Fig. 2 is a perspective rear view of a portion of thebaseplate,showing the longitudinally-movable detent-plate mountedthereon. Fig. 3 is a partial sectional plan View. Fig. I is a partialsectional plan View taken at the other end of the switchboard, showingone of the circuitmaking plungers or push-buttons pushed into itsoperative position. Fig. 5 is a diagrammatic view illustrating theconnections and circuits of a telephone instrument combined with aswitchboard constructed according to my invention; and Fig. 6 is apartial plan View of one of the parts, which I term a bridgepiece, withthe terminals which are secured thereon.

In'order to insure the successful working of the systems ofintercommunicating or connected telephones which are now ordinarilyemployed, it is essential that any desired instrument of the systemshould be connected so that it can be readily called up from any one ofthe other instruments.

In some of the systems of intercommunieating or connected telephoneswhich are now employed distinctive calls for the various instruments aresounded upon the call-bells,

One especial object which I have had in view in arranging the systems ofintercommunieating telephones in connection with which myswitchboardsare designed to be employed is to connect each instrument so that itscall-bell will not be sounded except when connection is desired withthat particular station.

In most of the systems of intercom m unicating telephones now used theinstruments are connected by wires, which are bunched to gether orassembled in the form of a cable, two strands or wires being used foreach instrument. In the use of switchboards in connection with telephonesystems of this character it is essential that the connections should beaccurately made by the switchboards without liability toshort-circuiting or other disarrangement. It has also heretoforeordinarily been essential that after one of the instruments of. thesystem has been used the connections which were made in the switchboardfor the purpose of connecting should be cut out and the switchboardrestored to its normal position, as itis quite possible that if any oneswitchboard of the entire system should become disarranged or should beleft in improper condition the entire system might be thrown out ofworking order, and in my application for patent filed April 22, 1897,Serial No. 633,326, I have shown and claimed a switchboard in whichconnections are made in a somewhat similar manner to that in which theyare made in the switchboard herein illustrated; but in the constructionshown in my aforesaid application for patent the circuit-making deviceswere intended to be automatically released and al lowed to return totheir normal position by means of connections from the hook upon whichthe receiver of the telephone was to be hung.

A further especial object of my present invention is to arrange thetelephone system so that it will not be necessary to release thecircuit-making devices either automatically or otherwise when the use ofthe instrument is finished, and I have provided a form of switchboardwhich will retain any one of a series of circuit-making devices in itsoperative position until another one of the circuit-making devices isoperated-that is to say, a telephone-switchboard constructed accordingto my invention comprises a plurality of normally open circuit-makingdevices and a detent mechanism for holding the circuit devices in theirclosed or operative position said parts being arranged so that when onecircuit-making device is operated the circuitmaking devicepreviouslyoperated will be released and allowed to assume its normalposition. 1

In its preferred construction and as herein described my switchboardcomprises a face-plate having a plurality of plungers or push-buttonsmovably mounted therein.

I have illustrated in the present case two rows or series ofpush-buttons; but the number or arrangement of course can be varied, asdesired. Cooperating with a conical actuating-piece mounted on eachplunger or push-button are a pair of spring-terminals or normally opencontact-pieces, which tend to push the plunger back to its normalposition. The plungers having conical operating-pieces to cooperate withnormally open spring eontact-pieces operate in substantially the samemanner as the corresponding parts shown in my application for patentbefore referred to, except that the relative position of the parts isreversed. Secured upon or forming part of each plunger or push-button isa steppingpiece having the shape of a double cone or double cam.Cooperating with the stoppingpieces of the several push-buttons of theswitchboard herein illustrated is a l0ngitudinally-movable perforated sin'ing-pressed de tent-plate.

\Vhen anyone of the plungers or push-buttons of my switchboard isoperated, the front incline of its conical stop-section will cam over orshift the movable detent-plate far enough to bring the edge of aperforation therein opposite the rearwardly-inclined conical or camsurface of the stopping-section of any plunger or push-button which mayhave been previously pushed in, so that said previously-omratedpush-button will be free to be forced back under the pressure of thspring-terminals coacting therewith to its normal position. 'When thestopping-section of the plunger which is being pushed in has passedthrough the perforation of the detentplaie corresponding thereto, thedetent-plate will be longitudinally shifted by its springs to hold theplunger in its operative position. Thus when any one push-button orplunger is operated the plunger or push-button which had been previouslyoperated will be released and will be forced back, so that theelectrical connections controlled thereby will be broken. By partiallyoperating any one of the plungers, but not pushing the plunger in farenough, so that the detent-plate can engage behind its stop-section, apreviously-operated plunger or push-button can be released withoutallowing the detent-plate to lock or socure the plunger being opera-tedin its forcedin position.

Referring to the drawings and in detail, 10 designates a face-plate orbase-piece which is preferably made of hard rubber or other insulatingmaterial. Secured upon the back of the face-piece 10 are perforatedbridgepieces 11, which are also preferably formed of hard rubber and aresecured in place by means of screws 21, as shown most clearly in Figs. 3and .4. Mounted in perforations in the face-plate 10 and bridge-pieces11 are mov-' able plungers or p ush-puttons 11-, two rows of suchpush-buttons being illustrated herein, but the number of suchpush-buttons being capable of variation, as desired. Secured on thepush-buttons 1lare conical operatingpieees 10, formed of insulatingmateriahas hard rubber.

Carried on the bridge-pieces ll and extending in position to cooperatewith the operat ing-sections 16 are spring contact-pieces 12, which areinsulated from each other, as shown in Fig. (3, and are arranged tocooperate with but are normally out of engagement with spring-lingersextending from plates 13, mounted on insulating-strips 18, as shown mostclearly in Fig. 1.

Secured upon or forming part of the stem of each plunger or push-buttonis a steppingsection 17, having a chainfered or inclined rear edge.

The plungers or push-buttons 11- extend through perforations in alongitudinally-movable detent-plate 19, which normally tends to move inone direction under the influence of springs 20, as shown most elearlyinFig. 2.

When a plunger or push-button is forced in, as shown in Fig. l, thedetent-plate will be first shifted by the stoppingsection 17, and afterthe stopping-section of the plunger has passed the detent-plate 19 willspring back behind the stopping-section 17 and will hold the plunger 11- in its operativeposition. lVhenever another push-button is operated,the detent-plate 19 will be shifted far enough so that the edge of theperforation corresponding to the plunger or push-button previonslyoperated will be brought opposite the chamfered part or incline formingthe rear edge of the stopping-section of said p ush-button, leaving thepush-button to be free to be restored to its normal position under thein fluence of its spring contact-strips 12. The same result may beaccomplished by countersinking or chamfering the inside corners of theperforations in the detent-plate.

By partially operating any one push-but ten the other push-buttons whichhave been previously operated will be released from the control of thedetent-plate 19.

The wiring or electrical connections between the parts of a telephoneinstrument employed in connection with a switchboard constructedaccording to my invention are illustrated diagrannnatically in Fig. 5.As

ITO

shown in this figure, A designates the switchboard, one pair ofterminals to a of which are the terminals to which the line-wires fromthe cable S, corresponding with the telephone instrument, illustrateddiagrammatically, are connected. B designates the call-bell of theinstrument. 0 designates the generator or dynamo-electrical machine usedfor calling in the ordinary manner. a designates the calling-switch. Ddesignates the battery; F, the induction-coil; G, the receiver; II, thereceiverhook, and E the transmitter.- The wires connecting these severalinstrumentalities can be readily followed in said Fig. 5, and, as shown,the bell or calling-circuit of each instrument is normally in circuitwith the line-wires corresponding therewith. In the operation of atelephone system as thus wired a subscriber whose call-bell sounds toreply to the call has simply to take down his telephone and push in thepush-button or plunger corresponding to his own instrument, so as toconnect the terminals to a to the bars 13 of the switch, which willthrow the speaking and receiving circuits off the instrument onto theline-wires a a, so that one can then talk to the person who has switchedhis telephone onto the line-wires a a at any point in the system.

hen it is desired to send out a call from an instrument in a system ofintercommunicating telephones constructed according to my invention, itis simply necessary to push in the desired push-button or plunger andsend a call over the line by means of the callingswitch and generator inthe ordinary manner, When a conversation has been ended, the person whohas been called up and the subscriber making the call are not requiredto restore their switchboards to normal conditions, nor is it necessarythat the switchboards should be automatically restored to normalcondition, and thus by constructing the switchboards of anintercommunicating telephone system so that the operation of acircuit-making device will release the circuit-makin device which hadbeen previously operated I am enabled to provide a simple, inexpensive,and positive system of telephonic intercommunication which will notreadily get out of order and which requires no release of parts eitherautomatically or by the persons using the system after a conversationhas been finished.

I am aware that changes may be made in the construction of myswitchboard for telephone systems by those who are skilled in the art,and I do not wish, therefore, to be limited to the construction or tothe particular arrangement of connections which I have herein shown anddescribed; but

lVhat I do claim, and desire to secure by Letters Patent of the UnitedStates, is-

1. In a telephone-switchboard, the combination of a plurality ofcircuit-making plungers or push-buttons, each having an inclinedstopsection, and a longitudinally-movable detentplate cooperatin g withsaid push-buttons, the engaging surfaces of the push-buttons and thedetent-plate being chamfered or inclined in the opposite direction tothe stopping-section of said push-buttons, whereby when a p ush-buttonis operated, previously-operated push-buttons will be released beforethe pushbutton being operated comes to its operative position,substantially as described.

2. In atelephone-switchboard, the combination of a plurality ofpush-buttons or plungers, each having a conical operating-section, twospring-arms engaging the conical section of each plunger to normallyforce said plungers outwardly, a contact-piece cooperating with eachspring-arm, whereby each plunger is adapted to make two electricalconnections when pushed in, a conical stop-section carried by eachplunger, and a perforated longitudinally-movable detent-platecooperating with said plungers, one or both of the engaging edges of thedetent-plate, and the stop-section of each plunger being chamfered orinclined in the opposite direction to the incline of the stop-section,whereby previously-operated plungers will be released and allowed toassume their normal positions before the plunger being operated comes toits operative position, substantially as described.

In a telephone-switchboard, the combination of a face-plate 10, aplurality of springpressed plungers 14 mounted therein, each plungerhaving a cam-operating section 16, and a double cone, stopping-section17, a pair of normally-open, spring contact-arms 12 cooperating with andengaging the operatingsection 16 of each plunger and normally tending toforce each plunger outwardly, and a longitudinally-movable detent-plate19 having springs 20 connected thereto, so that said detent-plate willtend to engage behind the stoppingsection of each plunger when the sameis pushed in, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

EDWIN W. HAN.

Witnesses:

PHILIP W. Sourncarn, Louis W. Sournoirrn.

